The brother of the teen charged with killing 17 people at a Florida school was arrested Monday afternoon for trespassing at the same school, authorities said.

Zachary Cruz, 18, was arrested at Marjory Stoneman Douglas High School and charged with trespassing on school grounds, a Broward Sheriff's Office report said.

The teen was recorded by security cameras riding his skateboard at the school around 4:30 p.m. though he had received prior warnings from school officials to stay away from the campus, the report said.

Zachary Cruz told the arresting deputy that he was there to "reflect on the school shooting and to soak it in," according to the report. It added that the teen had "surpassed all locked doors and gates and proceeded to ride his skateboard through school grounds."

The youth's brother, 19-year-old Nikolas Cruz, has been charged with 17 counts of first-degree murder in connection with the Feb. 14 shooting.

The Associated Press reported Sunday that documents show some officials recommended in September 2016 that Nikolas Cruz be involuntarily committed for a mental evaluation, though the recommendation was never acted upon. Such a commitment would have made it more difficult, if not impossible, for Cruz to have legally obtained a gun such as the AR-15 assault-style rifle used in the shooting.